Has anyone tried, or plan on trying, to fly the new Loki 38mm K1127 in a min diameter rocket? A quick and dirty sim showed 23k and M2.9. This is a project I would love to attempt, but unfortunately I don't have the hardware (easy fix) or the waiver space (not so easy fix) required to do so. Thoughts anyone?
Minimum Diameter K1127?
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RocketHunter
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I have a flying-case for the 38/1200 thats waiting for a launch to fly. The K1127 could put me a bit close to URRG's waiver so I'll probably go with the J-1000. You wont get M2.9 with a traditional MD - you'd need to be ~9-10oz with everything but the motor. Mine is ~9oz, and all it is is a fincan, a short 5'' section of CF tubing, and a thin-wall FWFG NC. 23K is pretty optimistic too - mine realistically sims to 19K on a J1000, and I'm expecting/hoping for 17-18k. It'll be an awesome flight when i get around to it - ~125 g's off the pad and ~M2.85... should nicely burn up some paint 
blackbrandt
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Connor Mcgrath (conman13) built one but hasn't flown it yet.
what crazy bastard would try this? (I posted an hour ago )
https://www.rocketryforum.com/showt...-community-build-thread&p=1481248#post1481248
I'm thinking M2 is a maybe, and around 18-20K
)https://www.rocketryforum.com/showt...-community-build-thread&p=1481248#post1481248
I'm thinking M2 is a maybe, and around 18-20K
I have a flying-case for the 38/1200 thats waiting for a launch to fly. The K1127 could put me a bit close to URRG's waiver so I'll probably go with the J-1000. You wont get M2.9 with a traditional MD - you'd need to be ~9-10oz with everything but the motor. Mine is ~9oz, and all it is is a fincan, a short 5'' section of CF tubing, and a thin-wall FWFG NC. 23K is pretty optimistic too - mine realistically sims to 19K on a J1000, and I'm expecting/hoping for 17-18k. It'll be an awesome flight when i get around to it - ~125 g's off the pad and ~M2.85... should nicely burn up some paint
Like I said, it was a quick and dirty sim. I'm sure a more detailed sim file would yield more accurate results.
As for the J1000 flight, is there thread I can subscribe to for it?
what crazy bastard would try this? (I posted an hour ago
https://www.rocketryforum.com/showt...-community-build-thread&p=1481248#post1481248
I'm thinking M2 is a maybe, and around 18-20K
Well good luck on that flight.
thanks. We'll see how it goes. I've got a lot of work to do before that flies.
Yeah. I just ordered parts to make my second 38mm MD. The first one fell apart on an I800 (0.5s burn in case your not familiar), 0.43s into the burn.
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Best the K1127 can do is about M2.5, based on my sims with a truly minimal rocket. I have a good bit of experience with this type of rocket, and have relatively high confidence in my sims.
Now, that's M2.5 with .05" 2024 fins glued to the case, a 10 x.032" payload section using a custom motor case as a coupler, and a partially hollow birch nose cone. This includes a 12" parachute, Merlin Tracker, 2 very small lipos, a RRC2+, and a Pico AA1.
Peak accel of 100G's and altitude of 15Kft.
All that adds a tiny 12oz to the weight of the motor.
https://www.mdra-archive.org/photos/redglare3/chuckrudy/Full/RG3BrianMach.wmv (similar rocket from a few years ago)
A "normal" minimum diameter rocket with an airframe I've simmed around M2.
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Normal is in around 11-13K
I just ran a sim of a fiberglass MD with a printed fincan, 36" wildman tube, and PC cone. Without any recovery it comes in at M2.2 and 11K.
I've always had rocksim be pretty accurate for 38mm rockets up to around M2.5, which is all I'm doing...
The M1.88 rocket in my video was ~10K, though it was a pretty crooked flight.
I just ran a sim of a fiberglass MD with a printed fincan, 36" wildman tube, and PC cone. Without any recovery it comes in at M2.2 and 11K.
I've always had rocksim be pretty accurate for 38mm rockets up to around M2.5, which is all I'm doing...
The M1.88 rocket in my video was ~10K, though it was a pretty crooked flight.
RocketHunter
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What are you using for your simulations? IMHO the K1127 should be able to go much faster than M2.5. If your rocket is only a mere 7.5 oz, you'd get a lot more than 100g - 130 g's per openrocket, which should be pretty darn accurate in predicting acceleration, as stuff like drag has a relatively small effect on the rockets peak acceleration. At 7.5 oz, you should be pretty close if not over M3. I attached my design file below. I set the finish to polished, and fins to rounded. I flew a 29mm MD to just under 10K, and the simulation using these parameters was within ~200 ft, so a polished finish in terms of drag is far from unachievable, as that rocket was far from perfect...
View attachment 38mm Flying Case.rkt copy.ork
I think rocksim isn't being very accurate here for you either... it is really not designed for mach+ simulations. 11-13K is simply way to low. I flew a 2+ lb Blackhawk 38 with 0.16" thick fins, a big, draggy slimline retainer protruding off the end, and multiple screws protruding into the airstream on a comparably small 973 N-s AT J570 and got ~11,500'. On a K1127 I'd easily expect over 13-14k, and if i removed the draggy slimline retainer (literally a square edge 1/8'' tall, not even rounded off, I just like it because it makes the rocket easier to fly) I'd bet it would go 15-16K easily, if not more. And if it was shortened, lighter, had thinner and more aerodynamic fins, etc., but still a traditional rocket, I'd expect 17k-19k.
bobkrech
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The 2015 maximum call-in waiver for Potter is 20 kft.
A 2 pound MD Go Devil 38 sims to ~17.74 kft on a Loki K1127. It sims to 17.84 kft, marginally higher, on a Loki 1026, and to 17.28 kft, marginally lower, on a Loki J1000. I actually think you are below optimum weight with a J1000 and will get about 17 kft. with it.I have a flying-case for the 38/1200 thats waiting for a launch to fly. The K1127 could put me a bit close to URRG's waiver so I'll probably go with the J-1000. You wont get M2.9 with a traditional MD - you'd need to be ~9-10oz with everything but the motor. Mine is ~9oz, and all it is is a fincan, a short 5'' section of CF tubing, and a thin-wall FWFG NC. 23K is pretty optimistic too - mine realistically sims to 19K on a J1000, and I'm expecting/hoping for 17-18k. It'll be an awesome flight when i get around to it - ~125 g's off the pad and ~M2.85... should nicely burn up some paint
Bob
That's why I said not so easy fix for waiver space. Plus a 6 hour drive out to potter is probably a once per year deal.
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